Refrigerating apparatus



Patented Nov. 20, 1934 UNITED STATES:

PATENT OFFICE 1,981,598 BEFRIGERATING APPARATUS- Jesse G. King, Dayton, Ohio Application October 30,

7 Claims.

during a temporary increase in the level of refrigerantin the evaporator.

It is a more specific object of the invention to .provide animproved oil return apparatus for a liquid cooling device of the type including a liquid cooling coil or conduit submergedin 'a body of liquid refrigerant contained in an evaporatorof a.

refrigerating system. 4

Further objects andadvantages of the present invention will be apparent from the following description, reference being had to the accompanying drawing, wherein a preferred form of the present invention is clearly shown.

In the drawing:

1 is a-sectional view of an evaporator having the invention incorporated therein and showing diagrammatically a refrigerating system operatively connected to the evaporator;

Fig. 2 is a view similar to Fig. 1 snowin ie position of the oil return device of the'inventi on during a period of increased level of refrigerant in the evaporator; and I Fig. 3 is an enlarged fragmentary sectional view of the elements constituting the improved oil re- .turn device disposed in the evaporator.

One of the problems in connection with a refrigerating system is that of the circulation .through the system of thelubricant supplied to the compressor for lubricating the moving parts of the compressor. The vaporized refrigerant is generally drawn to the compressor bysuction created by a pumping action in the compressor and on" being compressed is forwarded under pressure to the other elements ofthe'lefrigerat ing system. This process of suction, compressing and forwarding under pressure is apt to churn the oil into a foamy state and to carry a certain portion of it to other parts of the refrigerating sys tem where it is not desired,- Furthermore, as the' compressor generally'has the pumping action referred to, a certain pofizion of the oilis mechaniv 1933, Serial No. 695,757

(Cl. 62-141) v tion to that absorbed by the refrigerant. This oil eventually reaches the evaporator and where a refrigerant such as sulphur dioxide is used the oil will form a blanket on the top of the liquid refrigerant in the evaporator. If too much oil is drawn'from the compressor it may result in the moving parts of the compressor being damaged for want of sufficient lubrication. If the oil blanket becomes very thickon the surface 'of the liquid refrigerant in the evaporator it decreases the efficiency of the apparatus by taking the place of liquid refrigerant, and furthermore, by hindering suitable vaporization of the liquid refrigerant. Accordingly, it is one of the objects of this invention to provide means for returning any excessive oil in the'evaporator to the compressor.

In addition to the foregoing mentioned problems it is also a problem to prevent any liquid refrigerant from returning from the evaporator to the compressor with the oil. This latter problem is inherently present, particularly in apparatus wherein liquid cooling coils or conduits are submerged in the liquid refrigerant contained in the evaporator and utilized for circulating water, beeror the like through the evaporator to be cooled prior to dispensing the same. It has been found that devices for returning oil from the evaporator to the compressor of a refrigerating system wherein the evaporator thereof is employed to cool the interior of a refrigerator cabinet or the ;.like' are. not entirely satisfactory when incorporated in a water or beer cooler of the type dis-- closed. ,In liquid coolers, and particularly beer .coolers, wherein a large amount of beer'to be cooled is suddenly circulated in thermal contact with refrigerant within the evaporate, the great amount of heattransferred or given up to the refrigerant causes. refrigerant below the level thereof in the evaporator to boil violently; 'violent boiling or vaporization of the. refrigerant abnormal quantity of gas bubbles accumulating and flowing upwardly in the body of liquid refrigerant. The level of the body of liquid refrigerant and oil contained in the evaporator is thereby temporarily greatly increased and if no provision is made for the inlet opening of the oil return device to be raised relative to and simultaneously with the raising of'the level of refriger ant in the evaporator, liquid refrigerant will flow into the gaseous refrigerant returnpipe leading to the compressor. Liquid refrigerant upon being drawn into the'gaseous refrigerant. return pipe or swell, almost into a foam-like mass due to the and vaporizing therein will cause frosting over 5 quent warping or other damage to the floor or its coverings. This frosting of the return line also .in-'. creases the cost of operation due to theloss of; efliciency on account of the liquid refrigerant not beingevaporated or vaporized in the evaporator. It is therefore the main object of this invention to prevent thereturn of liquid refrigerant from the evaporator to the compressor in a system wherein the level of a body of liquid refrigerant in the evaporator intermittently changes while at the same time insuring the return of oil to the compressor during normal evaporation of refrigerant in or from the evaporator.

In Figs. 1 and 2 there is disclosed a type of evaporator, embodying a preferred application of the invention. This evaporator, generally referred to by the numeral 10, is preferably of the well-known flooded float control type. This evaporator as disclosed has a casing comprising a tank or boiler 11 having a closure or valve plate member 12 about its opening. It ispreferred to have a. supportingmember 13 about the opening of the tank member to receive the fastening means 14 for securing the valve plate in position. Suitable sealing/gaskets are of course inserted between the plate 12 and the supporting member 13. A manually actuated shut-off valve member 16 is attached to the exterior of the valve plate at the place of entrance of the inlet port 1'7. Surrounding this port 17 in the interior of the evaporator is a needle valve assembly, not shown, comprising a needleadapted to open and close a very small opening which communicates with the inlet port 17. This float control-valve may be of the type such as that disclosed in the patent to R. G. Osborn, No. 1,556,708, issued October 13, 1925. The operation of the needle .is controlled by a float ball 20 connected to the needle by a bracket arm 21, 0n the upper portion of the valve plate is located a manually actuated outlet shut-off valve 22 connected to the outlet port 23 for the vaporized refrigerant. The evaporator tank or casing 11 is surrounded on all sides by a layer of suitable insulating material 24, which material is enclosed in a casing 25. A conduit, coil or tank 26 may be disposed in the evaporator tank or'casing 11 below the liquid refrigerant maintained therein. This conduit or coil 26 includes an'inlet portion 2'7 and an outlet portion outlet port 23 which extends through the valve plate 12 (See Fig. 3); The pipe 30 is provided with a ball socket end 31 into which is fitted or located an outwardly extended ball portion 32 of a pipe or conduit 33. The opposite end of pipe 33 is provided with an outwardly extended ball portion 34 similarto the portion 32. Ball portion 34 of pipe 331s received or located vin a ball socket end 35 formed on a pipe or conduit 36.

Conduit 36. has secured thereto at 36a a float 37 and this conduit is bent downwardly so that the open end 38 thereof terminates at a predetermined point above the bottom of float 37. Each of the ball andsocket joints of the conduits 30, 33 and 36 form swivels or pivots for permitti g movement of conduits 33 and 36 in accordance with movement of the float 37. The joints between the conduits 30, 33 and 36 may be made in any suitable manner, and serve to render the portion of the suction line extending into the evaporator movable or flexible. Liquid refriger- .ant 40 fills the lower portion of the evaporator tank or boiler 11 to a predetermined height, determined by the calibration of the float ball 20. ,As this liquid refrigerant, which is preferably sulphur dioxide, vaporizes and flows to or fills the upper part of the boiler or tank 11 above the liquid refrigerant therein it is drawn through the pipes or conduits 36, 33 and 30 and out through the outlet port 23.

Refrigerant vaporized or evaporated in the boiler or tank 11 flows into conduit 36 through the open end 38 thereof and passes through the conduits 33and 30 to the outlet port 23 and hence to a refrigerant liquefying unit, a preferred form of which is illustrated diagrammatically in Figs. 1 and 2. A compressor 42 which generally has a pumping action, draws the evaoprated refrigerant by suction through the outlet 23 and a conduit 43 to the crankcase of the compressor. The vaporized refrigerant is then compressed by the compressor and forwarded under pressure to a condenser 44 where it is liquefied in any suitable manner and deposited in a receiver 45 until it is required by the evaporator 10, whence it passes through a conduit 46 to the inlet port 17 in the valve plate 12. The compressor 42 is preferably operated by a motor 48 operatively connected thereto through belt and pulley arrangements 49, 51 and 52. Any of the well-known controls may be employed for making and breaking an electric circuit to the motor 48 to start and stop operations of the compressor 42. Such control may be of the thermostatic type actuated in response to the temperature at the outlet of the water or beer cooling coil 26, or it may be of the type which is operated in response to pressures within the refrigerating system. However, either or both types of controls are now well known in the refrigeration art and further explanation thereof herein is believed to be unnecessary.

A considerable quantity of lubricant such as oil, is initially placed in the compressor 42 for the necessary lubrication of its moving parts.

As previously explained some of this oil is cara I ried along with the refrigerant during operation of the compressor and passes through the condenser and receiver and eventually reaches the evaporator. It is necessary, however, to return this oil to the compressor. only involves the return of the oil itself but the return of oil before the-oil blanket reaches a sufllcient thickness on the liquid refrigerant in the evaporator to seriously affect the efficiency of the evaporator. Furthermore, it is also necessary to return the oil without returning any liquid refrigerant, as such liquid refrigerant will cause frosting of the suction return conduit 43 thus causing a decrease in efficiency of the apparatus and also undesirable pools or puddles of water .on the floor. Accordingly, this invention contemplates the provision of means for returning the oil when it reaches a predetermined height, and furthermore, insuring that no ap-' preciable amount of liquid refrigerant will be drawn or sucked into the return conduit 43.

The float 37 is designed to float on top of the body of liquid or oil located above the body of liquid refrigerant in the evaporator so as to The problem not maintain the open end 38 of conduit 36 at a predetermined elevation above the layer of oil. The open end 38 of conduit 36 has been designed to cooperate with the float 37 so as to be disposed at substantially above the level of liquid refrigerant, because the thickness of the oil blanket on top of the-refrigerant should be maintained considerably less than or it will affect the efliciency of the apparatus. Of course the height of the open end 38 of conduit 36 could be placed at any desired height above the surface of a body of liquid refrigerant and oil that may be desired.

During evaporation of the liquid refrigerant in the evaporator the vaporized refrigerant has co-mingled therewith a quantityof oil, due to theaflinity of the oil for the refrigerant, and thus this vaporized refrigerant and the oil carried thereby forms a somewhat heavy fog. This fog is drawn by suction of the compressor into the open end 38 of conduit 36 and is returned to the compressor crankcase. Under ordinary conditions thisnormal evaporation of refrigerant and the carrying therewith of oil in the form of fog is ample to insure return of a sufficient amount of oil for properly lubricating the moving parts of the compressor. However, if provision to move the open end 38 of conduit 36 with the body of liquid in the evaporator is not providedin an apparatus of the type disclosed it is obvious that at one time or another during operation of the-system, liquid refrigerant will enter the conduit 36 and will then be returned to the compressor. By providing means whereby the open end 38 of conduit 36 may move up and down simultaneously with a rise or fall of the level of the body of liquid in the evaporator my invention completely eliminates the danger of withdrawing liquid refrigerant from the evaporator thereby insuring that only gaseous refrigerant and oil will be conveyed to the compressor.

During very active bubbling of the refrigerant in the evaporator, such as when a considerable amount of water or, beer is being circulated through the cooling coil 26 in the evaporator, a great quantity of bubbles form beneath the level of liquid .refrigerant in theevaporator thus causing the level to rise suddenly to a height above that normally maintained therein by the liquid refrigerant inlet float 20. The float 3'1 of my improved device being lighter than either the oil or liquid refrigerant in the evaporator,is

permitted by the pivoted ball and socket connections in conduits 30, 33 and 36 to follow the level of the body of liquid during its rise or fall in the evaporator. The expanded body or foamlike mass of liquid in the evaporator and the raised position of the float 3'7 and conduit 36 is clearly illustrated in Fig.3. It is apparent therefore that the open end 38 of conduit 36 is maintained in substantially constant spaced relation to the level of the body of liquid in the evaporator at all times. The spaced relation of the open end 38 of conduit 36 is predetermined so that during very active evaporation or bubbling of the refrigerant in the evaporator more oil may be returned to the compressor than during normal evaporation but no appreciable amount'of liquid refrigerant will be drawn into the return conduit.

While I am aware that oil return devices are not broadly new none of such devices known to me are or have been entirely satisfactory or suitable for use in an apparatus wherein a great amount of heat is suddenly or temporarily transferred or given up to a body of liquid refrigerant in an evaporator. In the use of known oil return devices in such apparatus wherein a water or beer cooler coil is submerged in liquid refrigerant cone tained in an evaporator the foregoing described rise of the level of the liquid in the evaporator causes liquid refrigerant to enter the suction line leading to the compressor. My improved apparatus therefore overcomes problems encountered in prior devices and accomplishes eflicient return of oil from an evaporator tothe compressor of a refrigerating system of the type wherein theevaporator is employed for cooling beverages such as water or beer, while at the same time insuring that substantially no liquid refrigerant will be returned to the compressor.

While the form of embodiment of the inventio as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

What is claimed is as follows:

1. A refrigerating system comprising in combination, an evaporator adapted to contain .abody of liquid refrigerant, means for normally preventing said body of liquid refrigerant from rising above a predetermined level in said evaporator, means for directing a liquid to be cooled through the body of liquid refrigerant in said evaporator whereby the refrigerant therein is caused to rise above said normal predetermined level, a compressor, a suction line communicating with said compressor and having a movable inlet disposed in said evaporator, and means operable independently of said first named means and controlled by the level of the body of liquid in said evaporator for maintaining the inlet of said suction line in substantially constant relation to the body of liquid in the evaporator.

2. A refrigerating system comprising in combination, an evaporator adapted to contain a body of liquid refrigerant, means for normally preventing said body of liquid refrigerant from rising above a predetermined level in said evaporator, means for directing a liquid to be cooled through the body of liquid refrigerant in said evaporator whereby the refrigerant therein is caused to rise above said normal predetermined level, a compressor, a suction line communicating with, said compressorandhavingamovable portion provided with an inlet disposed in'said evaporator, and a float secured to the movable portion of said suction line, said float being operable independently of said first named. means and controlled by the level of the body of liquid in said evaporator for actuating the movable portion of said suction line to maintain inlet thereof in substantially con-' level, a compressor, a suction line communicat- I ing with said compressor and having a flexible portion provided with an inlet disposed in said evaporator, and a float secured to the flexible portion of said suction line, said float being operable independently of said first named means and controlled by the level of the body of liquid in said evaporator for actuating the flexible portion of.

said suction line to maintain the inlet thereof in substantiallyconstant relation to the body of liquid in the evaporator.

4. A refrigerating system comprising in combination, an evaporator adapted to contain a body of liquid including refrigerant and oil floating on top of the refrigerant,- means for normally preventing the refrigerant in said evaporator from rising above a predetermined level, means submerged in the refrigerant in said evaporator for directing a liquid to be cooled therethrough whereby the body of liquid in said evaporator is caused to rise above said normal predetermined level, a compressor, asuction line communicating with said compressor and having a movable inlet disposed in said evaporator, and means operable independently of said first named means and controlled by the level of the oil in said evaporator for maintaining the inlet of said suction line in substantially constant relation to the surface of the'oil in the evaporator.

5, A refrigerating system comprising in combination, an evaporator adapted to contain a body of liquid including refrigerant and oil floating on top of the refrigerant, means for normally preventing the refrigerant in said evaporator from rising above a predetermined level, means submerged in the refrigerant in said evaporator for directing a liquid to be cooled therethrough whereby the body of liquid in said evaporator is caused to rise above said normal predetermined level, a compressor, a suction line communicating with said compressor and having a -movable portion provided with an inlet disposed in said evaporator, and a float secured to the movable portion of said suction line, said float being operable independently of said first named means and controlled by the level of the oil in said evaporator for maintaining-the inlet of said suction line in substantially constant relation to the surface of the oil in the evaporator.

6. A refrigerating system comprising in combination, an evaporator adapted to contain a body of liquid including refrigerant and oil floating on top of the refrigerant, means for normally preventing the refrigerant in said evaporator from rising ,above a predetermined level, means submerged in the refrigerant in said evaporator for directing a liquid to be cooled therethrough whereby the body of liquid in said evaporator is caused to rise above said normal predetermined level, a compressor, a suction line communicating with said compressor and having a flexible portion provided with an inlet disposed in said evaporator, and a float secured to the flexible portion of said suction line, said float being operable independently of said first named means and controlled bythe level of the oil in said evaporator for maintaining the inlet of said suction line in substantially constant relation to the surface of the oil in the evaporator.

7. A refrigerating system comprising in combination, an evaporator adapted to contain a body of liquid refrigerant, a float valve mechanism for normally preventing said body of liquid refrigerant from rising above a predetermined level in said evaporator, means for directing a liquid to be cooled through the body of liquid refrigerant in said evaporator whereby the refrigerant therein is caused ;to rise ab'ove'said normal predetermined level, a compressor, a suction line communicating with said compressor and having a movable portion provided with an inlet disposed in said evaporator and a float secured to, the movable portion of said suction line, said last named float being operable independently of said float valve mechanism and con-' trolled by the level of the body of liquid in said evaporator for actuating the movable portion of said suction line to maintain the inlet thereof in substantially constant relation to the body of liquid in the evaporator.

JESSE G. KING. 

